Characteristic imaging findings of the respiratory system in penguins with suspected aspergillosis in an aquarium

Abstract

Twenty penguins, including the King penguin (Aptenodytes patagonicus), Gentoo penguin (Pygoscelis papua), and African penguin (Spheniscus demersus), housed at an aquarium in Hokkaido, Japan, underwent regular health screening via blood test, and five penguins with suspected aspergillosis were extracted. In cases 1 and 2, a thickened membrane and/or fluid level and/or calcification in the air sac were observed on both radiography and computed tomography (CT). These two penguins died after 19 and 43 days, respectively. At the time the radiographic changes were observed, the disease had likely progressed to a point at which it was too late for recovery. Aspergillus fumigatus infection was confirmed by nucleotide sequence analysis in case 1. In case 3, infiltration in the pulmonary parenchyma was observed on CT, and the infiltration disappeared following oral administration of itraconazole as diagnostic therapy for 8 months. In case 4, defects in the pulmonary parenchyma were observed only on CT. These defects remained unchanged in size for 7 months despite the lack of any treatment, and were not considered clinically significant. However, the blood antigen level in case 5 was increased, both radiography and CT were unremarkable. The combination of a screening blood test and CT examination could be useful clues for an early diagnosis of aspergillosis as well as for initiating treatment.